asp.net C#把資料寫入到txt檔案中代碼

asp.net c#把資料寫入到txt檔案中代碼
bool checkfile = file.exists(filename);

  filestream fs = new filestream(filename, filemode.openorcreate, fileaccess.write);
  streamwriter sw = new streamwriter(fs, system.text.encoding.getencoding("gb2312"));//通過指定字元編碼方式可以實現對漢字的支援，否則在用記事本開啟查看會出現亂碼

  sw.flush();
  if (checkfile)
  {
  sw.basestream.seek(0, seekorigin.end);//移動到結尾
  }
  else
  {
  sw.basestream.seek(0, seekorigin.begin);
  }
  string temp = "隨便寫點東西www.111cn.net";
  sw.writeline(temp);
  sw.flush();
  sw.close();

 filestream fs = new filestream(path, filemode.create);
                streamwriter sw = new streamwriter(fs);
                    sw.writeline(textbox1.text);
                sw.close();
                fs.close();